This invention relates to an improved shock absorber arrangement and use therefor.
It is well known to employ various types of hydraulic dampers in connection with suspension systems, especially those associated with vehicles and particularly road vehicles. The shock absorber performs the function of dampening the cushioned movement of the wheel relative to the vehicle body and cooperates with the spring and linkage system to achieve this effect. Generally, hydraulic shock absorbers are employed and various damping arrangements are incorporated with them. Basically, the shock absorber damps the movement by passing fluid through an orifice. The degree of restriction may be either constant if a fixed orifice is used or variable if a variable orifice and/or pressure responsive valving arrangement is employed.
Although these systems have been found to be quite effective, they nevertheless do present some problems because of their very nature. For example, it has been found that handling can be significantly improved if very small relative movements of the wheel relative to the frame are positioned in a generally undamped fashion. That is, a small amount of movement of the wheel relative to the vehicle body can be desirable even when that movement is undamped.
In accordance with an important feature of this invention, therefore, it is an object of the invention to provide a hydraulic damping arrangement wherein relatively small degrees of suspension movement may be accommodated without significant damping forces.
It is a further object of this invention to provide an improved damping arrangement for a hydraulic shock absorber wherein small amounts of fluid displacement are permitted without significant restrictions so as to achieve the aforenoted effects.
In accordance with the invention, this degree of relatively undamped movement can be accommodated by providing a chamber in which an elastic member is positioned. The chamber is exposed to the pressure chambers of the shock absorber on opposite sides of the elastic member. Thus, small movements can be accomplished by pressurizing the chamber and having the elastic member shift from one position to another without actually causing fluid flow to occur between the chambers. This shifting movement is relatively undamped.
Of course, there may be some displacement of fluid due to compression of the elastic member, and this elastic compression can give some degree of damping, although relatively slight in relation to the overall system. Nevertheless, this permits the shock absorber to be tuned to provide very good response under all conditions.
It is, therefore, a still further object of this invention to provide an improved damping arrangement and fluid flow system of this type utilizing an elastic member that is interposed between a pair of hydraulic chambers of the damper.
In order to permit the desired degree of relatively undamped movement, some displacement of fluid is required. In order to permit the necessary displacement of fluid and in accordance with a further feature of the invention, the elastic member comprises an elastic ring that is received in an annular cavity. Obviously, this cavity must be in sealing relationship between the sides of the ring so as to preclude significant flow of fluid past the ring, while still permitting the ring to move within the chamber. Obviously, this presents certain problems with the installation and assembly.
It is, therefore, a still further object of this invention to provide an improved fluid damping arrangement that is comprised of a cylindrical cavity in which an elastic ring is received.